Extrusion apparatus and method



March l1. 1947. v. JAcoBsoN l y EXTRUSION APPARATUS AND METHOD Filed April 18, 1944 l Nh E... .L

.EEE NEEM@ 1 l 'vuvwmlrom-v Vdctorfhcoxon BY mmnmfwd ITTORN E YS i Patented Mar. 1 1, 1947 v v Ex'rausxoN ArPAaA'ros AND rm'rnon Victor Jacobson, Hastings on Hudson, N. vY.l Application Anni 1s, 1944, serial No. 531,531

This invention relates provision of an improved method and apparatus for extruding various shaped articles of plastic materials through a forming die. More parto the extrusion of man#` c. tic elongated articles and has for its object the be in the formofa die and may be provided with a shearing edge for removing the excess y plastic material which flows into the relief outticularly, theinvention contemplates the provi-4 sion of an'improved apparatusand method for -v l extruding plastic sheaths on electricalconduc-` tors,vbars, and the like with greater eiilciency and more uniformity of product. j

The invention' isespecially applicable vto the so-called continuouslextrusion operations such as' arecommonly used in lthe sheathing'of conductors, and provides means for the interruption and the starting of the operation without ap'- pre'ciably irripairing the continuity and unitormity of the j extruded plastic material. For ex.

ample, in the drawing of a wire through a die.

which'forms a sheath over. the wire, it is fre-4 quently necessary to interrupt the drawing of the wire'. The plastic material, however, continues to flovw.A and when the operation is 'resumed'.

there is an imperfection manifested by ridges and other enlargementson .the sheath that im' Apairs the value of the product.v The present invention overcomes this drawback and enables the operation to be interrupted and resumed with- Y.

out impair-ingl the product.

uniformity of the -extruded The apparatus of the inventioncomprises any i Y suitable extrusion devices for extruding a the r. fmoplastic, orlike' material, through a forming die, relief outlet l.mear'is for'receivlng excess plas` y `tie material flowing through-the die when the operation is interrupted, vand a supplementary',

shaping member to remove any enlargements formed on the extruded product as a result of g the interruption.' Thereliei' outlet for the plassupplementary shaping member preferably surrounds the extruded product and shapes the product to the proper size immediately follow,- ing resumption of the operation.

In an advantageous embodiment of the inven.

` .Q tio material is a space contiguous with the die opening at the outlet side of the die and the" tion, the apparatus may be in the form` of a twopart die, the first die performing the usual shaping operation and the second die being spaced f from the first die and in the direction of travel of the extruded product. A space, preferably an annular space, is providedbetween the dies which serves as a relief youtlet' for the excess material which continues to i'low from the nrst.

die when the operationis interrupted. The sup'- plementary shaping member may, accordingly,

let during interruptions. One or more knives maybe mounted in the space between the two .y

dies to slice the material forced through the relief outlet and thereby facilitate its removal.

These and other novel features of the inven- 'tion 'will be better`understood after considering the following discussion taken in conjunction Vwith the accompanying drawings. in which:

Fig. 1 is a longitudinal sectionalview of ap.

paratus embodying the invention;

Fig. 2 is Fig. Y2i is other adaptation tion.

The apparatus .iiiustratcc'll in Figs'. 1 and 2f comprises-an annular sloping inner wall member I, partly in the form of a truncated cone. having an opening 2 for centering and guiding the conductor or wire 3 drawn therethrough, and

a die member 4 spaced from the wall member in the direction oi' travel of the wire and having the die opening 6 ofsuch diameter that it will form a sheath 1 around the wire of 'the desired thickness. The die member preferably' v has a sloping wall 8 spaced from the wall member I to form a conically shaped passage s therebetween which-is contiguous with thejspacebel 3 tween the die opening and the wire 3. The wall y.

member I and die are provided with an exterior housing Irwhich not only serves to secure thetwo elements together as a rigid structure-but provides a chamber II contiguous with the conical space 8 for the plastic material.

The plastic material is supplied to the cham#- ber II under pressure through the opening I2. The, supplementary shaping member II is in the s form of a die surrounding .the sheathed conduci tor and has a die opening I6 of the same inside diameter as the exterior diameter of the sheath 1.' (The die members 4 and I5 are referred to herein as the first and second die members respectlvelv.) rigid spaced relation with respect tothe die member 4 in any suitable manner, as by means of the bolts I1 and I8, These bolts may be provided with left and right threads by' means of i which the annular space I9 between the die mem -V bers 4 and I5 may be adjusted. In an advantageous embodiment of the invention, a knife edle 2l is provided on the die member Il toshear oil any excess of plastic material that may be Price a view along the line if-l'of-lfls. 1,

a" longitudinal .sectional view of of the apparatus ofthe inven# The die member II is mounted in on the exterior of the sheath, as will later be explained. In a preferred arrangement; two diametrically disposed and longitudinally extending knives 22 and 23 are m-e-unted in the ane nular space I9 to split an)1 material forced therethrough and thus facilitate its removal. In carrying out a, method of the invention in the apparatus illustrated, any suitable hot plastic material may be used to form the sheath that does not adhere to the die members, such as vinyl acetates and vinyl chloride, marketed under the trade name Vinylite, or the rubber-like composition sold under the trade name Koroseal. The plastic material at the proper temperature is forced under pressure into the chamber II from which it flows through the passage 9 and through the die opening 6 forming the sheath 1. In a normal continuous operation, the sheath 1 has a 4knives 22 and 23 and may, accordingly, be removed in two parts. When the operation is resumed, the material in the outlet space I9, which is actually contiguous with the sheath portion, is sheared off to the proper exterior diameter by the knife edge and the die opening I6 serves to smooth out the sheath to normal uniformity.

There is, therefore, no noticeable difference inthe the interruption of the operation.r

It isv understoodthat the apparatus may be' heated in any suitable manner as by means ofacoil orjacket for the circulation therein of a heated fluid, such as steam or oil.

' The apparatusl illustrated in Fig. 3 comprises a chamber which is supplied with plastic materia] under pressure through the pipe' II. outlet of the chamber is in the form -of a die 32 having any suitable cross sectional shape, for example, square, octagonal. or cylindrical, and the plastic material forced therethrough is in the form of a rod 33. The supplementary shaping member 34, also in the form of a die, surrounds the rod and has a knife edge 35 for shearing oiI excess material and a pair of knives 36 and 31 to slit the material. The bolts 38 and 39 support v the member 34 in adjustable spaced relation with respect to the opening of the die 32. 'I'he annular relief outlet space 40 performs a function similar to that described in connection with the apparatus of Figs. 1 and 2. The apparatus is especially useful for thermoplastic materials, and, when such materials are used, the apparatus may be heated in any suitable manner when necessary. It is understood, of course, that the apparatus is not limited .to the use of thermoplastic materials and may` be used to form objects of any plastic material. The apparatus of Fig.' 3 may be used, for example, in forming rods and the like of predetermined lengths. Each time a length is cut off there may be a momentary interruption, and the invention eliminatesl any irregularities which may result from such interruptions.

The apparatus of Fig. 3 may be used in connection with plastic molding apparatus, in which case the rod 33 may be extruded into anysuitable mold and in which the plastic material may be given any desired shape. In this adaptation of `aeration l35. exterior appearance of the sheath by reason o f The the invention, the apparatus serves a moldfllling means and the relief outlet space 40 as a A pressure relief means preventing any excessive finished article, intcrruptlngfthe movemng d@ finished article away from the formingl die 'While' jv excess material is forced through the die, passing, d

y excess material flowing throughtheI die lto a "a:

relief opening, resuming the movement of the nnished article away from the die, removing irregu- 15 larities from the extruded product resulting from the interruption by shearing offthexss mate- L rial, and passingthe extruded product supplementary forming operation. .-"J

a plastic state which comprises a chamber for containing the material to be extruded under pressure, a rst die through which the material is forced to ilow from the chamber, a second die, said second die havingv its,inlet opening 25 spaced from the outlet opening 'of the ilrst die to provide a space between said dies which forms a relief outlet for material forced from the first 'die opening when an extruding operation is interrupted. c

a plastic state as set forth In claim 2 in which at least one'knife is located in the space between the two dies and so positioned as to split excess material forced into said space and facilitate its removal.

4. Apparatus for the extrusion of material in a plastic state as set forth in claim 2 in which a cutting edge is provided around the die openingin the second die to shear of! excess marial accumulating in the space between the two 5. Apparatus for the extrusion of material in 2. Apparatus for the extrusion of material in ,amish l 3. Apparatus. for the extrusion of material in a plastic state as set forth in claim 2 in which a cutting edge is positioned around the die opening in the second die to shear ofi' excess material accumulating in the space between the two dies and at least one knife is located in said space and so positioned as to split excess material forced into the space and facilitate its removal.

6. Apparatus for the extrusion of material in a plastic state which comprises a chamber for containing the material to be extruded under pressure, a first die member having a die opening through which the material is forced to flow from the chamber, a second die member having y;

a die opening of substantially the same size and shape as the die opening in the first die member and substantially in alignment therewith.

the inlet to the die opening in the second die member being spaced from the outlet of the die opening of the ilrst die member to provide a space between said dies which forms a relief outlet for material forced from the.` rst die member when an extruding operation is interrupted, said second die member serving to remove irregularities on the surface of material extruded through the first die" member resulting from an interruption in the .xtruding operation causing enlargements where" the excess material ows into said space.

7. Apparatus for4 the extrusion of a sheath of material in a plastic state around a wire or the like which comprises a chamber for containing I.

the plastic material to be extruded under 'pressure, a rst die member having a die opening through which the wire is passed, said chamber communicating with said die opening so that a wire passed through the die opening will have a sheath of the plastic material formed about it, a second die member through which the sheathed wire leaving the first die member passes to remove any irregularities on the surface oi. the sheath resulting from an interruption of the extruding of the sheath, the inlet to spaced from the outlet of the first die opening to provide a space between said die vmembers having a die opening` the second die opening being.

which forms a relief outlet for material forced from the first die opening when an extruding operation is interrupted.

8. Apparatus for the extrusion of a sheath of material in a plastic state around a wire or the like as set forth in one knife is located two dies and so positioned as to split excess said space and facilitate extrusion of a sheath of material forced into its removal.

9. Apparatus for the claim 'I in which at leastl in the space between they 6 material in a plastic state around a. wire or the like as set forth in claim 'i in which a knife edge isI located in the space between the two dies and so positioned as to shear oiI excess materia1 resulting from an extruding operation,

and at least one knife is located in said space and so positioned as to split excess plastic material forced into such space to facilitate its removal.

VICTOR JACOBSON.

REFERENCES CITED The following reierences are of record in the ille of this patent:

" UNITED STATES PATENTS Number Name Date 2,233,928 Weaver Mar. 4, 1941- 2,348,591 Bailey May 9, 1944 2,218,751. Humphrey Oct. 22, 1940 FOREIGN PATENTS yNumber Country Date British June 26, 1935 

